sprinkler one shot timer

[emmett]

Hi again group. Have a friend that has coons and possums that are
messing with his swimming pool. He set up a motion sensor to turn a
110v sprinkler valve on, and wants it to stay on for a minute or so,
but the water keeps on "falsing" the sensor. I am trying to come up
with a simple timer delay that would be set off by the motion sensor
and would then be in charge of turning the sprinkler valve off after a
minute or so regardless of motion input. Kind of a one shot mode. I am
having a mental block with the 110v though as to how to interface that
with a timer. Am I trying to complicate this? Don't know what the
specifics are as to motion sensor sensitivity etc. Any suggestions?
Thanks much !! Wayne

 

[JeffM]

[...]He set up a motion sensor to turn a 110v sprinkler valve on,
and wants it to stay on for a minute or so,
Wayne

Well, you HAVE that.

but the water keeps on "falsing" the sensor.
[...]Am I trying to complicate this?

What you're doing is *not dealing with THE PROBLEM*.

If *motion* AFTER shutdown is the problem,
you need a **deadband**
where you disable the trigger until things are still again.
This requires a *second* timer which trips at the OFF point of the
first.

 

[[email protected]]

Hi again group. Have a friend that has coons and possums that are
messing with his swimming pool. He set up a motion sensor to turn a
110v sprinkler valve on, and wants it to stay on for a minute or so,
but the water keeps on "falsing" the sensor.

Try putting the sensor out of view of the water...

 

[emmett]

Try putting the sensor out of view of the water...

Very true on both fronts I realize it needs a timer to turn the water
on then another
way of turning the water off for 30 seconds or so. I'm stimyed as to
how though. I did tell him to try a different lens on the MS like
sunglasses or aiming it different I'll have him try that first before
I build a 556 timer board if he feels it is that important Again for
your time and expertize I am truly grateful I'll be back. Wayne

 

[Jamie]

Hi again group. Have a friend that has coons and possums that are
messing with his swimming pool. He set up a motion sensor to turn a
110v sprinkler valve on, and wants it to stay on for a minute or so,
but the water keeps on "falsing" the sensor. I am trying to come up
with a simple timer delay that would be set off by the motion sensor
and would then be in charge of turning the sprinkler valve off after a
minute or so regardless of motion input. Kind of a one shot mode. I am
having a mental block with the 110v though as to how to interface that
with a timer. Am I trying to complicate this? Don't know what the
specifics are as to motion sensor sensitivity etc. Any suggestions?
Thanks much !! Wayne

Use a Timer relay with 2 sets of contacts for the trip cycle.
A delay off type would be good. One set of contacts will lock it
on, and the other set of contacts will disable the sensor. Many
timer relays will reset it's timer if the input retriggers and thus
it may not expire.
And for the sensor, you should have a time on delay power source that
was interrupted from the first timer to disable it. The reason for this
is, when the main timer expires and turns it self off. This would then
reconnect the sensor. If water is still in the air, you'll get a false
start. Using a delay on timer for a power source to run the sensor will
fix that.
SO basically, first timer is a Delay OFF type using one set of it's
own contacts lock on the input signal. the other set of contacts will
disconnect the power to the Time on delay relay for the sensor..
When first relay expires. it'll turn on the delay on relay for the
sensor. mean while, water in the air should be clearing.
when the delay on sensor expires., the contacts will then close to
allow sensor activity once again.

You can actually do all of this with a 556 timer, (dual 555).
the first timer will be the delay on for the sensor, the Reset line
of this timer will be controlled from the output side of the second
timer etc...

 

[ehsjr]

Hi again group. Have a friend that has coons and possums that are
messing with his swimming pool. He set up a motion sensor to turn a
110v sprinkler valve on, and wants it to stay on for a minute or so,
but the water keeps on "falsing" the sensor. I am trying to come up
with a simple timer delay that would be set off by the motion sensor
and would then be in charge of turning the sprinkler valve off after a
minute or so regardless of motion input. Kind of a one shot mode. I am
having a mental block with the 110v though as to how to interface that
with a timer. Am I trying to complicate this? Don't know what the
specifics are as to motion sensor sensitivity etc. Any suggestions?
Thanks much !! Wayne

Simple. What you really need to do is keep the motion
sensor from being set off by the water from the sprinkler
system. Use a relay to interrupt power to the sensor,
or output from the sensor, when the sprinkler is on.
The drop out of the relay is delayed by a capacitor, so
the water will finish falling befor the sensor is
turnde back on.

The relay will be driven by a transistor, which will
be held in the on state for a few seconds after the
sprinkler turns off. I'll draw an NPN circuit as an
example, which takes a plus 12 from the sprinkler
when the sprinkler is on, to turn the relay on. (When
the relay is on, the sensor is interrupted.)

+ 12 ----------+---[Rly]---+
| |
+-----|<----+
|
Sprinkler /c
Plus>---+---[1K]---+-----| NPN
| | \e
[10K] [470uF] |
| | |
Gnd ----+----------+-------+

In effect, the transistor amplifies the capacitance,
delaying the dropout *much* longer than if you simply
placed the cap in parallel with the relay coil. The
delay will depend on the transistor gain and relay
coil resistance, but should be a few seconds. You
can change that to a few minutes, if you want, by
using a darlington transistor and increasing the 10K
to 1meg, or make it variable by using a 1meg pot
with the darlington.

Ed

 

[neon]

Look up LM555 use it as a oneshot input 2 that will run once untill next transition and i don't think you got 110 volts springler system there is probably 24 v ac transformer in between. for false triggering use another LM555 in series to provide a dead band of time. And use the 24v volts tranformer as a power souce. too complicated ask for more help.

 

[zhafran]

Hi again group. Have a friend that has coons and possums that are
messing with his swimming pool. He set up a motion sensor to turn a
110v sprinkler valve on, and wants it to stay on for a minute or so,
but the water keeps on "falsing" the sensor. I am trying to come up
with a simple timer delay that would be set off by the motion sensor
and would then be in charge of turning the sprinkler valve off after a
minute or so regardless of motion input. Kind of a one shot mode. I am
having a mental block with the 110v though as to how to interface that
with a timer. Am I trying to complicate this? Don't know what the
specifics are as to motion sensor sensitivity etc. Any suggestions?
Thanks much !! Wayne

Simple. What you really need to do is keep the motion
sensor from being set off by the water from the sprinkler
system. Use a relay to interrupt power to the sensor,
or output from the sensor, when the sprinkler is on.
The drop out of the relay is delayed by a capacitor, so
the water will finish falling befor the sensor is
turnde back on.

The relay will be driven by a transistor, which will
be held in the on state for a few seconds after the
sprinkler turns off. I'll draw an NPN circuit as an
example, which takes a plus 12 from the sprinkler
when the sprinkler is on, to turn the relay on. (When
the relay is on, the sensor is interrupted.)

+ 12 ----------+---[Rly]---+
| |
+-----|<----+
|
Sprinkler /c
Plus>---+---[1K]---+-----| NPN
| | \e
[10K] [470uF] |
| | |
Gnd ----+----------+-------+

In effect, the transistor amplifies the capacitance,
delaying the dropout *much* longer than if you simply
placed the cap in parallel with the relay coil. The
delay will depend on the transistor gain and relay
coil resistance, but should be a few seconds. You
can change that to a few minutes, if you want, by
using a darlington transistor and increasing the 10K
to 1meg, or make it variable by using a 1meg pot
with the darlington.

Ed

Sorry to interrupt. May I know what is indicated by that symbol just
below the relay (Rly) in the circuit diagram shown

 

[emmett]

Simple. What you really need to do is keep the motion
sensor from being set off by the water from the sprinkler
system. Use a relay to interrupt power to the sensor,
or output from the sensor, when the sprinkler is on.
The drop out of the relay is delayed by a capacitor, so
the water will finish falling befor the sensor is
turnde back on.

The relay will be driven by a transistor, which will
be held in the on state for a few seconds after the
sprinkler turns off. I'll draw an NPN circuit as an
example, which takes a plus 12 from the sprinkler
when the sprinkler is on, to turn the relay on. (When
the relay is on, the sensor is interrupted.)

+ 12 ----------+---[Rly]---+
| |
+-----|<----+
|
Sprinkler /c
Plus>---+---[1K]---+-----| NPN
| | \e
[10K] [470uF] |
| | |
Gnd ----+----------+-------+

In effect, the transistor amplifies the capacitance,
delaying the dropout *much* longer than if you simply
placed the cap in parallel with the relay coil. The
delay will depend on the transistor gain and relay
coil resistance, but should be a few seconds. You

Diode

can change that to a few minutes, if you want, by
using a darlington transistor and increasing the 10K
to 1meg, or make it variable by using a 1meg pot
with the darlington.

Ed

Sorry to interrupt. May I know what is indicated by that symbol just
below the relay (Rly) in the circuit diagram shown- Hide quoted text -

- Show quoted text -

 

[zhafran]

emmett wrote:
Hi again group. Have a friend that has coons and possums that are
messing with his swimming pool. He set up a motion sensor to turn a
110v sprinkler valve on, and wants it to stay on for a minute or so,
but the water keeps on "falsing" the sensor. I am trying to come up
with a simple timer delay that would be set off by the motion sensor
and would then be in charge of turning the sprinkler valve off after a
minute or so regardless of motion input. Kind of a one shot mode. I am
having a mental block with the 110v though as to how to interface that
with a timer. Am I trying to complicate this? Don't know what the
specifics are as to motion sensor sensitivity etc. Any suggestions?
Thanks much !! Wayne
Simple. What you really need to do is keep the motion
sensor from being set off by the water from the sprinkler
system. Use a relay to interrupt power to the sensor,
or output from the sensor, when the sprinkler is on.
The drop out of the relay is delayed by a capacitor, so
the water will finish falling befor the sensor is
turnde back on.
The relay will be driven by a transistor, which will
be held in the on state for a few seconds after the
sprinkler turns off. I'll draw an NPN circuit as an
example, which takes a plus 12 from the sprinkler
when the sprinkler is on, to turn the relay on. (When
the relay is on, the sensor is interrupted.)
+ 12 ----------+---[Rly]---+
| |
+-----|<----+
|
Sprinkler /c
Plus>---+---[1K]---+-----| NPN
| | \e
[10K] [470uF] |
| | |
Gnd ----+----------+-------+
In effect, the transistor amplifies the capacitance,
delaying the dropout *much* longer than if you simply
placed the cap in parallel with the relay coil. The
delay will depend on the transistor gain and relay
coil resistance, but should be a few seconds. You

Diode

can change that to a few minutes, if you want, by
using a darlington transistor and increasing the 10K
to 1meg, or make it variable by using a 1meg pot
with the darlington.
Ed

Sorry to interrupt. May I know what is indicated by that symbol just
below the relay (Rly) in the circuit diagram shown- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

ahh yes.exactly.thanks